I received my DTA last fall, and since getting, I’ve mostly been working on load development pretty much the entire time. My DTA is in 300 win mag, and a lot of the recipes I’ve tried have been recommendations from here on The Hide. The most popular is the combination of H1000 and 208gr Amax. I had absolute no luck with any combination I tried with H1000 and 208 Amax. I started with a ladder test, which told me almost nothing, and I then went on to just shooting groups at 100yds with different combos. I got something that worked OK, and it shot pretty consistent out to 750. However, after 750, the round started doing crazy stuff, like being a foot off in elevation (high or low). I’ve been shooting for a fair amount of time, but came to the conclusion that I must suck fairly bad. I had a seasoned buddy try my same load out of my rifle, and he couldn’t shoot it well either. I was a bit frustrated to say the least, as I had gone through about 250 rds and still hadn’t gotten something solid figured out.
Zak, from Thunderbeast, recommended trying H4831SC, and I’m so glad he did. I tried a few different loads, and things tightened up significantly! I experimented with seating depth this weekend, and finally got a solid load that I feel good about going forward with. My best 5 shot group was right about a quarter of an inch at 100yds. Below are a couple of pictures. The first being on paper, the second was the cardboard behind the paper with a dime for comparison.
Using the Hornady O.A.L gauge, the 208 A-max touches the lands at around 3.606 in my rifle. From there, I experimented with seating depths at 3.606, 3.595, and 3.585. My best results were with a 3.595 seating depth, which is about 0.010 off the lands. I got good results with 3.585 as well, but I pulled a round and the group didn’t look as nice, though I think going with 3.585 would yield good results as well. Below is what worked well in my rifle, but of course this isn’t going to work for everyone, but may give you some ideas:
Winchester Brass, already fire formed, and cut/chamfered/de-burred with Giraud case trimmer to 2.610 after having been neck sized using the 0.333 bushing in a Redding die on a Forster press.
71.5 grains of H4831SC
208 A-Max
COAL of 3.595
Federal GM215M Primers
Average Velocity - 2,881
Extreme Spread - 41
Average Deviation - 13
Standard Deviation - 16
Energy - 3,836
The bipod is a GG&G Extreme duty and the suppressor is a Thunderbeast 30P-1. I’m using a Vortex PST 4-16x, FFP MRAD with the DTA Rings with inserts. After yesterday, I’m seriously considering getting a S&B PMII 5-25x. The Vortex is solid, but I feel like it’s definitely a bottleneck at this point in terms of clarity and reticle thickness.